sadly so far it is very hard to actually charge batteries.
You can find cheap regulators :
http://www.ev-power.eu/Solar-GridFree/Solar-PWM-Regulator-12-24-V-10A-Input-30V-50V-LS1024E.html?cur=1
I think you are vastly overestimating what Power you will get from a solar panel.
It's all about how much and where you invest off course , but even this old article shows how much potential solar power has :
http://www.huffingtonpost.com/michael-graham-richard/can-we-power-the-whole-wo_b_104355.html
We could have "free" global solar energy
If you google Gobi desert + solar energy you see the Chinese understand that:
https://www.hongkongfp.com/2015/07/13/nasa-images-highlight-the-stunning-growth-of-solar-farms-in-china/
You could pump some water in a high ground reserve and when you need power, use the gravity and water to power hydroturbine! 
I laughed. Yeesssss of course.... A kinetic battery, why not?
Let me just pump 10 pool worth of water over my head, to last the night on my S5
Not so crazy : https://en.wikipedia.org/wiki/Energy_storage#Renewable_energy_storage
Thank you all for contribution